1. Field of the Invention
The present invention relates to a communication terminal device such as a facsimile machine provided with codec (coder and decoder) means which differ from one another in communication ability.
2. Description of the Related Art
According to a facsimile machine of the conventional G3 mode, when carrying out facsimile communication by using V.34 method of the ITU-T Recommendation having a communication speed exceeding 14.4 kbps and lower than 28.8 kbps, it is necessary to code or decode image data by using a codec circuit formed by a hardware circuit. On the other hand, when carrying out the facsimile communication by using a method equal to or below V.17 method of the ITU-T Recommendation having a communication speed equal to or less than 14.4 kbps, the image data is coded or decoded by using a codec program of software stored in a storing device.
According to the conventional facsimile machine, in the case the facsimile machine comprises only one codec circuit formed by the hardware circuit, in addition to the codec program of the software, there were problems in that while the facsimile communication is being carried out, for example, an image cannot be read by an image reading unit and the image data cannot be coded to be stored into an image memory, or the image data within the image memory cannot be read and decoded to be printed out by an image printing unit.
Moreover, according to such a conventional facsimile machine, during scanning by the image reading unit or during printing by the image printing unit, when time reaches the scheduled time at which the registered transmission is to be carried out, even if the other end has the communication ability based on V.34 of the ITU-T Recommendation, the facsimile machine is required to carry out the facsimile communication by using the codec program of the software and by using the method having the communication speed equal to or lower than the communication speed of V. 17 of the ITU-T Recommendation. Therefore, compared with a required communication time in the case in which the facsimile communication is carried out by using the codec circuit formed by the hardware, the facsimile communication needs an especially long communication time, and accompanying this, there was a problem in that the communication expenses became excessive.